Britain's austerity spending cuts would mean a reduction of 14,000 in the number of military personnel, a 10 per cent reduction from the current staffing level of 137,000.

Some UK politicians have been calling for an increase in defence spending, taking it from two to three per cent of GDP.

Russia a real threat

Speaking at the Royal United Services Institute, General Carter said:

"Russia I think could initiate hostilities sooner than we expect and a lot earlier than we would in similar circumstances. Most likely they will use nefarious sub NATO Article 5 treaty actions to erode the capability of Nato and threaten the very structure that provides our own defence and security. This is the divide and rule which the international order is designed to prevent."

He noted that the Kremlin already boasted an "eye-watering quantity of capability", as demonstrated by ostentatious war games held under the international gaze in recent years. There were "not thousands of miles away but are now on Europe's doorstep".

By contrast the British military has increasingly outdated equipment, and a black hole in its budget, with further deep cuts planned for the coming years.